Effect of modified starch-chitosan coating incorporated with Gongju extract on the shelf life of salted duck.

Abstract

This study developed and characterized acetylated distarch adipate/chitosan (ADA/CS) coating incorporated with Gongju extract (GE), investigating its effects on the quality of salted duck during storage. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) results confirmed the formation of hydrogen bonds among ADA, CS and GE, leading to tightly cross-linked polymerization. The incorporation of GE disturbed the internal interactions within the matrix, thereby reducing the barrier, mechanical and thermal properties of the coating. The coating exhibited superior antioxidant activity during cold storage, with DPPH scavenging rates ranging from 44 % to 64 %. The ADA/CS/GE coating effectively delayed lipid and protein oxidation in salted duck by releasing antioxidant components. At the end of storage, the total volatile basic nitrogen (TVB-N) value of the ADA/CS/GE group was 5.51 mg/100 g lower than that of the control group. Additionally, the total viable count (TVC) and Pseudomonas count were reduced by 1.92 and 0.66 log CFU/g, respectively. The salted duck treated with the ADA/CS/GE coating maintained pH, texture and moisture content, ensuring the overall quality of the product. These results indicated that the ADA/CS/GE coating effectively extended the shelf life of salted duck by 9 days at 4 °C.